Simulator is PC based software to simulate actual MAINFRAME working environment. Simulator has its own limitaions in the sense that it cannot work exactly like actual mainframes. Simulator is used mostly for training new comers.

Simulator is an Open Mainframe. Using that it's possible to simulate the Mainframe system in a PC. But the speed, reliability, security & parallelism are very very poor. Simulator simulates a virtual platform to run mainframe OS & some mainframe application software in the PC.

If you just want to learn about s/390 and zseries check out Hercules which is free (but can only officially run public domain operating systems like MVT and an early VM or any of the 390 versions of Linux).

You cannot get ISPF environment in Herculas. Try Microfocus or MVSBench Simulators.

Sorry, but it is possible to get ISPF software on Hercules...
Hercules is an emulator for an IBM machine.
You can put any IBM code on it and theoretically, it should run as it would on a real MF machine.
If you want ISPF on Hercules...copy the ISPF files to your emulator and run as usual.

Simulator is an Open Mainframe. Now it is possible to simulate the Mainframe system even in a PC. But the speed & parallelism are very poor. They exactly run All mainframe OS & Software in cheaper Cost.

Simulator is an Open Mainframe. Now it is possible to simulate the Mainframe system even in a PC. But the speed & parallelism are very poor. They exactly run All mainframe OS & Software in cheaper Cost.